170 BIOLOGICAL LECTURES. 



causal science, can never reach completeness, since every new 

 cause ascertained only gives rise to fresh questions regarding 

 the cause of this cause. 



Inasmuch as many of its problems are nearly or quite in- 

 soluble by means of experimental investigation, developmental 

 mechanics must needs, so far as possible, seek to utilize for its 

 own ends, all the kinds and ways of causal investigation of 

 organisms and the resiilts thereby attained, and not cast aside as 

 useless any biological discipline in silly conceit. Develop- 

 mental mechanics should, moreover, cultivate the analysis of 

 formative processes into constant "complex components" to a 

 greater extent, if anything, than the ascertainment of simple 

 components. 



This conception of the methods of investigation first to be 

 undertaken in developmental mechanics differs essentially from 

 the views of many contemporaneous workers in the same field, 

 who believe that descriptive and comparative anatomy as well 

 as embryological investigation are of little value to develop- 

 mental mechanics. This opinion is held by authors who see 

 the present task of developmental mechanics in the immediate 

 reduction of organic formative processes to purely inorganic, 

 physico-chemical components (14). 



If, however, we limit ourselves to that which is possible at 

 present, we can regard this task only as a final goal, which for 

 the present, and even for some time to come, we shall approach 

 in a direct path only at a relatively slow pace ; still we are not 

 to cease in our endeavors " to reduce the formative forces of 

 the animal body to the general forces or vital tendencies of the 

 world as a whole," as K. E. von Baer has said (15). 



It is evidently advantageous, and will be productive of much 

 important information, if we endeavor to reproduce syntJietically 

 in an inorganic way structures, forms, and processes which resem- 

 ble as closely as possible, or are the same as those of the organic 

 world. This has been done by G. Berthold, Errera, and more 

 recently, and with marked success, by O. Butschli. 



Were we, however, to follow this as the only method of pro- 

 cedure, and, in accordance therewith, to attempt the investiga- 

 tion only of those processes which resolve themselves at once 



